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Comment: Re:Alternate Bank of Canada Press Release (Score 1) 218

by mirix (#49186335) Attached to: <em>Star Trek</em> Fans Told To Stop "Spocking" Canadian $5 Bill

Here's the rules, FWIW. Pennies are only valid to 25c.

(2) A payment in coins referred to in subsection (1) is a legal tender for no more than the following amounts for the following denominations of coins:

        (a) forty dollars if the denomination is two dollars or greater but does not exceed ten dollars;

        (b) twenty-five dollars if the denomination is one dollar;

        (c) ten dollars if the denomination is ten cents or greater but less than one dollar;

        (d) five dollars if the denomination is five cents; and

        (e) twenty-five cents if the denomination is one cent.

Comment: Re: Star Wars! (Score 4, Interesting) 253

by mirix (#49162621) Attached to: 20-Year-Old Military Weather Satellite Explodes In Orbit

These ran NiCd cells. Here's some TL;DR from NASA about a variant of NiCd they use(d), not sure if it applies here.

Short notes:
Fancy NiCd, Higher density and sealed. They rely on precise chemistry to be hermetically sealed units (lean on one element, for limiting and only O2 production).
High pressure at full charge (~60PSI at room temp), higher if things go south, Pressure drops with charge state.
Excess discharge causes hydrogen production.

So, tin can, pressure changing with charge cycles (metal fatigue over many cycles?), H2 production, O2 production... maybe there is some chance for catastrophic failure there.

Comment: Re:Perhaps it wouldn’t pass today’s .. (Score 2) 286

by mirix (#49077111) Attached to: 1950s Toy That Included Actual Uranium Ore Goes On Display At Museum

I'd imagine more harmful to ingest/inhale uranium ore... in addition to radioactivity, uranium is also a heavy metal like lead. (in both senses of the term "heavy metal".)

However most ore is quite weak, with 1% being pretty decent... I think it's economical to mine it as low as 0.1%. A few mines in Canada are near 20%, though (which I suppose is related to Canada being the biggest producer... 1/5th the ore is end product, instead of 1/1000th!). Ore will often have lead and such in it as well (decay products), which is also toxic.

Comment: Re:consumerism wins! (Score 2) 294

by mirix (#48995857) Attached to: Radioshack Declares Bankruptcy

It might be different in the US, but in Canada they always had terrible stock. So if your thing didn't have a broken lamp or speaker, or a dead battery - you were SOL, as they didn't carry anything else.

There's so much different silicon now that it isn't really feasible to stock even a small portion of it in every mall anyway, so most anything you fix you'll have to order in parts for...

It would have been more reasonable when I was a kid (and they only stocked a whopping 3 transistors and zero fets then, too).

Comment: Re:What happens to these at the true end-of-life? (Score 2) 143

by mirix (#48541467) Attached to: Using Discarded Laptop Batteries To Power Lights

Lithium cells are pretty benign in general. There are a few variants in chemistry, the worst would probably be the cobalt based ones. (others use various combinations of iron, nickel, manganese, and phosphorous, which are pretty tame). Though the cobalt variants are quite common.

NiCd is far worse, cadmium is fairly nasty... much more than cobalt.

Research is what I'm doing when I don't know what I'm doing. -- Wernher von Braun